PROJECT SUMMARY/ABSTRACT Sustained viral suppression (VS) continues to present major challenges to HIV treatment and prevention. Retention in care is a particularly challenging issue for persons living with HIV (PLHIV) because of lack of convenient access and issues related to economic stability. Our long-term goal is to help achieve the 90-90-90 goals through improved care delivery based on rigorous implementation research. The objective of this project is to demonstrate the effectiveness and longer-term sustainability of a differentiated care delivery model for improving HIV treatment outcomes. The central hypothesis is that the integration of HIV care delivery and community-based primary care with group-based microfinance will improve retention and rates of VS among PLHIV in Kenya via two mechanisms: improved household economic status and easier access to care. Thus, the specific aims are as follows: (1) To evaluate the extent to which integrated community-based HIV care with group microfinance affects retention in care and VS among PLHIV in rural western Kenya using a cluster randomized intervention design of existing (fully HIV+) microfinance groups to receive either: (A) integrated community-based HIV care, or (B) standard care. We will also augment trial data with a matched contemporaneous control group of patients in standard care (group C) comparing outcomes in groups A, B and C; (2) To identify specific mechanisms through which microfinance and integrated community-based care impact VS: Using a mixed methods approach, we will characterize the mechanisms of effect on patient outcomes. We will conduct quantitative mediation analysis to examine two main mediating pathways (household economic conditions and easier access to care), as well as exploratory mechanisms (food security, social support, HIV- related stigma). We will also use qualitative methods and multi-stakeholder panels to contextualize the implementation of the intervention; and (3) To assess the cost-effectiveness of microfinance and integrated community-based care delivery to maximize future policy and practice relevance of this promising intervention strategy. Our working hypothesis is that the differentiated model will be cost-effective in terms of cost per HIV suppressed person-time, cost per patient retained in care, and cost per disability-adjusted life year saved. This project is part of the Academic Model Providing Access to Healthcare (AMPATH) program in western Kenya which cares for more than 150,000 PLHIV at over 500 sites in western Kenya since 2001. The main expected outcomes will be rigorous evidence of effectiveness, mechanisms and cost-effectiveness of a differentiated model for achieving the last key step in the HIV care continuum. These results are expected to have an important positive impact in terms of improved, high-quality services that address known individual and structural barriers to care and promote long-term sustainability of care for PLHIV in rural settings with high HIV prevalence.